A fast, mobile-first calculator with shareable results and inflation-aware math.
| # | Date | Contribution | Interest | Balance |
|---|
Copy-ready snippets (code is hidden; click to copy).
Iframe is simplest. Loader injects a responsive iframe and accepts data-goal, data-monthly, data-rate, data-infl, data-inflon.
We compound monthly. Nominal monthly rate = (1+annual)^(1/12)−1. If inflation is on, we first convert your annual return to a real rate using (1+return)/(1+inflation)−1 and then compound monthly. Each month: balance grows by rate, then the monthly contribution is added.
Nominal returns ignore inflation and make targets look closer. Real returns account for purchasing power—useful if your goal (e.g., $1M) is in today’s dollars.
We don’t model taxes directly, but you can approximate them by lowering your annual return (e.g., use your after-tax, after-fee return). A 7% market return with ~1% combined tax/fee drag ≈ 6% effective. Small fee differences compound a lot over long horizons.
Yes—add the monthly value of your match to your contribution. Example: If you earn $5,000/month and your employer matches 4%, add $200/month to your contributions. If your match caps at a certain amount, only include up to that cap.
The calculator assumes a constant average return. Real markets swing, so for conservative planning either: use a lower return (e.g., shave 1–2% off your expectation), or boost contributions a bit to build a margin of safety.
Yes—enter it as your starting balance (best) or add it to the first month’s contribution. A lump sum earlier generally beats spreading it out because it compounds longer.
Our default adds contributions at end-of-month. If you contribute at the beginning, each deposit gets roughly one extra month of growth. As a rule of thumb, that’s like multiplying each month’s deposit by (1 + monthly rate)—a small edge that compounds over time.
Sure. Convert to a monthly equivalent: Weekly × 4.333 ≈ monthly; Biweekly × 2.167 ≈ monthly. Using more frequent real-life deposits is fine—just keep the math consistent by entering the monthly total.
Yes. Pick a target date and goal-seek by adjusting either the contribution or the return until the “Years to $1M” lines up. For a realistic plan, keep returns within historical ranges and prioritize adjusting contributions first.
Short-term drops happen. Two ways to stay on track: build a buffer (use a slightly lower return in the calculator), and set a rule to temporarily increase contributions after down years. Consistent contributions during downturns often buy more shares at lower prices, improving long-term results.
If you’re unsure, a long-term assumption around 2–3% is common in the U.S. Use the real return option if you want your goal shown in today’s dollars; otherwise, nominal results will look larger but include inflation’s effect.
Yes—run it in phases: years with contributions (phase 1). Then set contributions to $0 and continue compounding (phase 2). Combine the timelines to see your total time to $1M.